Most decisions in life require a balance of sorts and choosing to buy or build a solar oven (solar cooker) is no exception. There are literally a handful of main solar oven design types and these are the solar box oven, the panel cooker, the parabolic cooker, a solar kettle, a solar hybrid cooker and a funnel cooker.
There are other solar oven designs in addition to these six categories that are used, for example a hot dog solar cooker, but by-and-large the majority of solar cookers fall into one of these categories.
The box cooker is probably one of the most basic solar oven designs and is literally a box concept that is designed to allow maximum sunshine to go into the insulated inner box and heat the food in an appropriate solar cooking pot or pan. The heating effect is amplified by having the unit sealed with a transparent material, either buffered glass or a thick polyethylene-kind plastic.
A very popular example is the Global Sun Oven, arguably the most extensive solar oven in the world. These cookers generally are good value for money, easy to use, commercially produced, effective and popular. On the downside is these cookers can be quite bulky and not as portable as some of the smaller designs. A smaller home-made variant is the solar pizza oven.
The panel cookers use flat, shiny, reflective panels to focus and concentrate sunlight onto a cooking pot that is enclosed in a clear plastic bag. basically it is similar to the box cooker concept except in the majority of panel cooker designs there is no internal box. An example of a panel cooker is the CooKit solar oven. These cookers are very easy to use and light-weight, although do not quite unprotected to the same internal temperatures as the solar box oven peer.
Solar kettles are slightly less noticeable and less shared compared to the other cooker designs. The solar kettle uses an evacuated solar glass tube (solar vacuum glass tube) constructed from borosilicate glass to capture and store energy from the sun. This design is also referred to as a solar kettle-thermos flask. An advantage is that these cookers can heat liquids to high temperatures and retain a comparatively high temperature for most of the evening outside of daylight hours. Whilst some cooking of food is possible, this is limited compared to the traditional solar cookers.
Parabolic cookers are a more complex solar cooker design and whilst extremely effective in both domestic and industrial applications, these cookers do tend to be more pricey than their peers and as such are largely unaffordable for the entry-level solar user. These designs also tend to be quite large and not particularly portable.
A hybrid solar oven is a concept that endeavors to provide the best of both worlds for solar cooking and traditional cooking. It is essentially a box cooker designed with a traditional electrical heating component which compensates for weather conditions where the box solar cooker is either unable to perform or potentially performs poorly. Probably the most widely used form globally is the Tulsi-Hybrid Solar Oven. The main obvious disadvantage of this cooker is the occasional cost of electricity.
The funnel cooker is simply a less complex variant of a basic panel cooker design. As opposed to having various definite panels forming part of a network of panels surrounding the cooking pot, the funnel cooker is simply a complete funnel designed with the funnel inversely flared, in other words the open end of the funnel closest to the sun is open wide and flared inwards down to a closed bottom, where the cooking pot is positioned. Whilst one of the less effective cookers, this does have the additional advantage of being very portable and very quick and easy to construct.